[Amps] GS23B Plate load resistance for HF

[Peter Voelpel]

Efficiency goes up with higher anode voltage.

With a 2m push-pull and 4KV on the anodes we obtain 60% easily (5 out)at the
DK3EE EME station.

73
Peter

-----Original Message-----
From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Jeff Blaine
Sent: Donnerstag, 31. Oktober 2013 04:36
To: Bill Turner; Amps
Subject: Re: [Amps] GS23B Plate load resistance for HF

Bill,

Thanks for the update.

I think the GS35b is a lot like the general soviet style of the time - big 
and functional, but not very elegant.  ha ha.

It's not a great tube functionally, but it looks cool and I've been enamored

with the beast for years.  I've GOT to build an amp with it just to get that

out of my system.  ha ha.

Thanks.

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message----- 
From: Bill Turner
Sent: Wednesday, October 30, 2013 10:24 PM
To: Amps
Subject: Re: [Amps] GS23B Plate load resistance for HF

ORIGINAL MESSAGE:          (may be snipped)

On Wed, 30 Oct 2013 21:18:51 -0500, Jeff wrote:

>Bill,
>
>Did you use a tuned input on those two amps?  The reason I asked is that I
>saw quite an interaction between the efficiency of my gi7b and the tuned
>input trimming that I was never really able to figure out.
>
>Also, what tank Q did you build the design around?
>
>I'm planning to build a GS35b amp for the higher bands this winter.
>
>73/jeff/ac0c
>www.ac0c.com
>alpha-charlie-zero-charlie

REPLY:

Yes, I always use a tuned input on my amps. Design Q for the output tank was
12 per the G4AXX spreadsheet.

You might be interested to know that in both amps, I replaced the GS35b with
an 8877, changed the cathode zener and filament transformer and immediately
got into the 60%+ efficiency range. The HV and input and output circuits
were the same. The only conclusion I can come to is the tube itself just
isn't as efficient as others.

As I said, if you can accept the 10% or so reduction in efficiency,
everything else about the tube is good. Especially the price.

When you build your amp, you can use a Coleman lantern replacement glass for
the chimney. It fits perfectly and can be fastened to the chassis with a few
dabs of silicon RTV, which is easily removed with a knife if you ever have
to. And of course, it needs no socket, just some careful metal work and some
simple home made clamps.
Have fun!

73, Bill W6WRT
_______________________________________________
Amps mailing list
Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps 

_______________________________________________
Amps mailing list
Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps